1. Field of the Invention
This invention pertains to a non-rigid composite sheet having fire resistant properties. The sheet is useful as walls in a cargo container, particularly containers used in aircraft as well as in other applications where containing the spread of fire is important.
2. Description of Related Art
Cargo containers or unitary load devices (ULDs) are used in aircraft, ships, road vehicles and railcars to carry goods. For economic reasons there is a desire to reduce the weight of an empty container while minimizing its operational cost. Shipment of flammable materials in air cargo containers is creating a serious safety issue for airlines and air cargo carriers. There is increasing concern about the capability of existing containers to contain the spread of fire when the ignition source is the cargo itself. An example of such an ignition source is a lithium-ion battery. Consequently, to prevent possible human casualties and cargo equipment losses, airlines and air cargo carriers are looking for flame resistant cargo containers to contain fires that may originate within the containers. A tightening of regulatory requirements is expected over the next few years. There is therefore a need to provide a light weight cargo container having enhanced capability to contain the spread of fire from within the container that meet stringent durability standards while providing an extended lifetime with minimum maintenance.
U.S. Pat. No. 8,292,027 to Richardson et al describes a composite laminate comprising in order (a) a flame retardant polymeric moisture barrier (b) an inorganic platelet layer and (c) a flame retardant thermoplastic film layer.
United States patent application publication 2003/0170418 to Mormont and Jacques discloses a protection product having thermal and acoustic barrier characteristics such that it satisfies the requirements of the standard 14 CFR, part 25 issued by the Federal Aviation Administration. The product is designed to be applied along metallic and composite structures, such as aircraft cockpits, boat hulls or the outside structures of trains or of other means of transport. The product is essentially in the form of a “mat” consisting of one or several fiber layers, preferably glass fibers, enclosed in a sheath. The sheath generally comprises at least one first support, preferably made of an organic material having sealing and anti-condensation properties, and an impregnated mica paper. The mica paper preferably has a weight per unit area of less than 50 gsm and comprises flakes of mica with a form factor greater than 1000.
U.S. Pat. No. 6,884,321 to Erb at al describes a flame and heat resistant paper having high burnthrough prevention capability, as required in aircraft applications. The paper is prepared from modified aluminum oxide silica fibers, in addition to other components, and has exceptional tensile strength and flexibility as compared to conventional inorganic papers.
United States patent publication number 2010/0304152 to Clarke discloses high hear resistant elastic composite laminates, sealants, adhesives, and coatings developed from a resin blend. The resin blend is made up of methyl and optionally phenyl silsequioxane resins selected to produce silanol-silanol condensation silicone polymers formed in a slowly evolving reaction mass containing submicron boron nitride, silica and boron oxide fillers. The required ratio of submicron boron nitride to silica has been discovered for assuring the formation of a high temperature resistant elastic composite blend that will form intermediate flexible ceramic products up to 600 degrees C., and then continue to form preceramic dense ceramic products from 600 to 1000 degrees C. The thermal yield of the composite is generally greater than 90 wt, % at 1000 degrees C. Composite products with different levels of heat transformation can be fabricated within the same product depending upon the thickness of the layers of reinforcement.
In a presentation entitled “Development of a Thermal/Acoustic Insulating Blanket Responding to the FAR 25.856 by the Integration of Mica Flame Barrier” at the Fire and Cabin Safety Research Conference in Lisbon on Nov. 18, 2004, Jacques and Orance describe the development of a mica paper for use in the construction of an aircraft fuselage.